Best Practices for Monitoring and Controlling California Red Scale in Citrus


California accounts for 32 percent of the U.S. citrus crop production, and in that geography alone there are several pests that threaten the California citrus industry.1 A particular concern to citrus growers is California red scale infestations, and it is crucial for growers to have solutions that will protect their crops and improve yields.

California red scale populations are seen throughout most of the citrus-growing regions of the state. These pests attack all above-ground parts of the tree by sucking on the plant tissues with their long, filamentous mouthparts. If red scale infestations are high, they can inflict serious damage to trees, such as leaf yellowing and drop, dieback of twigs and limbs, occasional tree death, and even fruit pitting or drop.2

To assess and monitor infestation rates, many citrus growers use pheromone traps during the first, second and fourth male flights, occurring in March, late May and August, respectively. However, it is important to understand that traps may not always be an accurate indicator of the efficacy of a red scale treatment.

“When using Movento to treat for red scale, it’s normal to have a high number of males on the pheromone trap card, as Movento targets immature and adult female scales,” said Steve Olson, Insecticide Product and Citrus Crop Manager at Crop Science. “When pheromone traps pick up a lot of male red scale, it can give a false sense that the insecticide is not working.”

Movento® insecticide from Crop Science is a unique and innovative tool for managing citrus pests like red scale. Active by ingestion, Movento has shown excellent results against immature stages of insects and adult female pests, reducing fecundity and limiting the survival of their offspring, therefore providing more effective overall reduction of pest pressure.

“Since Movento controls the adult female and immature populations, its effectiveness can be downplayed by the traps. The most important method to evaluate effectiveness of the product is to scout for scale on the leaves, twigs and fruit 30 days after application.”

According to trial data from the University of California, treatment with Movento resulted in the greatest reduction in red scale infestation over the course of the trial, when compared to competitive insecticides. California citrus treated with Movento at a spray volume of 250 gallons per acre (GPA) and 500 GPA reduced red scale populations from 24 percent to 1.1 percent and 25.5 percent to 3.1 percent, respectively.

What makes Movento so uniquely effective against red scale is its two-way systemic movement to all parts of the plant, resulting in more comprehensive pest control.

“Good insecticide coverage is important for red scale control,” Olson said. “There are very few products that are as effective on red scale today, so Movento is a really critical component. You’ll see a positive effect on your yields and tree vigor.”

Find out more about the benefits of Movento systemic foliar insecticide and how it can improve your citrus pest control management program.

Work Cited

1 “Pests a growing threat to citrus”

2-3 “How to Manage Pests: Citrus California Red Scale and Yellow Scale”

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